A meta-analysis of acoustic correlates of timbre dimensions

A meta-analysis of ten published timbre spaces was conducted using multidimensional scaling analyses (CLASCAL) of dissimilarity ratings on recorded, resynthesized, or synthesized musical instrument tones. A set of signal descriptors derived from the tones was drawn from a large set developed at IRCAM, including parameters derived from the long-term amplitude spectrum (slope, centroid, spread, deviation, skewness, kurtosis), from the waveform and amplitude envelope (attack time, fluctuation, roughness), and from variations in the short-term amplitude spectrum (flux). Relations among all descriptors across the 128 sounds were used to determine families of related descriptors and to reduce the number of descriptors tested as predictors. Subsequently multiple correlations between descriptors and the positions of timbres along perceptual dimensions determined by the CLASCAL analyses were computed. The aim was (1) to select the subset of acoustic descriptors (or their linear combinations) that provided the most generalizable prediction of timbral relations and (2) to provide a signal-based model of timbral description for musical instrument tones. Four primary classes of descriptors emerge: spectral centroid, spectral spread, spectral deviation, and temporal envelope (effective duration/attack time)